In EP0860461-A, there is described a process for the ring-opening polymerization of cyclosiloxanes, which comprises contacting a cyclosiloxane with 1 to 500 ppm of a phosphazene base, by weight of cyclosiloxane, in the presence of water. In GB 2311994, there is described a method of effecting polycondensing which comprises contacting at a temperature of from 0 to 200.degree. C. and a pressure up to 350 torr, a silanol-containing organosiloxane with an amount of a peralkylated phosphazene base which is effective for polycondensation of said organosiloxane. The preferred peralkylated phosphazene base has the formula ##STR1##
wherein R# is a C.sub.1-4 alkyl radical, R* is a C.sub.1-10 alkyl radical and n is 2 or 3. EP0879838-A describes a process of preparing a polymer which comprises conducting ring-opening polymerization of a 4- to 10-membered cyclic monomer in the presence of a phosphazenium salt catalyst of an active hydrogen compound represented by the formula ##STR2##